There is a long-standing prospect of using a single comb laser chip emitting multiple low-noise spectral modes for DWDM data transmission in the O-band. This goal is hindered by unacceptably high total power requirements for such a source to overcome losses in a PIC and to provide at least 1 mW per data channel in a fiber. We solve this problem by simultaneously re-amplifying more than 20 lines depleted after the PIC using a low-noise quantum dot (QD)-based SOA. In this way, we demonstrate O-band DWDM data transmission of a PAM4 signal with a total bit rate of up to 2.3 Tb/s in fiber with a single QD comb laser source. The other problem related to the application of semiconductor comb lasers is the insufficiently large interline separation to be compatible with the state-of-the-art DWDM PIC technologies. We present comb laser devices with and without a saturable absorber section, providing up to 23 lines with 100 GHz intermode separation, 10 lines with 138 GHz separation, 4 lines with 163 GHz separation, and 3 lines with 216 GHz separation, suitable for data transmission. We show that in the mode-locking regime, both the relative intensity noise (RIN) of the comb laser and the associated bit error rate (BER) are determined by the optical power of the laser mode.

We experimentally compare QD-SOA to QW-SOA, bulk-SOA, and PDFA for coherent and IM/DD in the O-band at 10 km. A 1.152 Tbps/λ WDM coherent transmission is achieved with the QD-SOA.

We report on O-band InAs/GaAs QD DFB laser with integrated SOA section, able to deliver more than 400 mW optical power with efficiency beyond 20% in 25-85 degrees C temperature range. This laser is perfectly suited for uncooled operation in ELS for CPO. (c) 2024 The Author(s)

We present monolithically integrated GaAs- based O-band quantum dot distributed feedback lasers with semiconductor optical amplifier sections, achieving output powers exceeding 430 mW. The proposed distributed feedback lasers operate over a wide temperature range of 25-105 degrees C with different detuning reaching - 40 nm. (c) 2025 The Author(s)

We experimentally evaluate the influence of the gain recovery time of a QD-SOA on IM/DD in the O-band and establish a way to estimate the gain recovery time of an SOA.

We report a continuous-wave, O-band quantum-dot semiconductor comb laser for WDM optical interconnects exhibiting a 2.2 THz optical bandwidth with up to 89 comb wavelengths spaced at 25 GHz, over 30% peak ex-facet electrical-to-optical power conversion efficiency, up to 270 mW of usable laser power, relative intensity noise below − 135 dB/Hz per individual mode, individual laser mode linewidth of 140 kHz, mode beating linewidths of 50 kHz across all modes, and stable far-field output with 75% coupling efficiency to PM fiber in a butterfly package.

The performance of a high-power single-mode InGaAs QD-based BOA providing 28dBm of output saturation power in 25÷85°C temperature range is presented. The studied BOA is targeted for 1.3μm LIDAR applications working in uncooled regime.

We experimentally demonstrate a 106 Gbps PON downstream signal transmission using a high-gain InAs/InGaAs quantum dot-based SOA as a preamplifier. We achieved a record-high power budget of 40 dB considering an HD-LDPC BER limit of 1 × 10 − 2.

High-power O-band Quantum Dot Distributed-Feedback Laser for pluggable DR4/DR8 optical transceivers and Remote Laser Modules is presented. It exhibits PCE as high as 20% up to 105°C and CW power exceeding 300mW at 85°C.

A compact passively Q-switched Nd:YAG laser was end-pumped by a water-cooled 808 nm vertical-cavity surface-emitting laser (VCSEL) pump module comprising four high power, high brightness VCSEL chips with a combined 10 mm diameter circular emitting area and 2.3 kW total peak power, resulting in 47 mJ laser pulse energy at 1064 nm with 16% optical efficiency at 15 Hz repetition frequency. A laser package comprising an air-cooled 1.6 kW VCSEL pump module produced 37 mJ laser pulse energy, while more than 13 mJ laser pulse energy was demonstrated in a bench-top experiment with a very compact laser set-up using a single 5 mm x 5 mm VCSEL chip.

High power 808nm semiconductor lasers are widely used for pumping neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal to produce high-brightness lasing at 1064nm. In addition, there are growing interest to use such high power 808nm lasers in the field of automotive infra-red (IR) illumination and medical aesthetic treatment. Vertical-cavity surface-emitting lasers (VCSELs) have emerged as a promising candidate and attracted increased interests for those applications, due to their combined advantages of high efficiency, low diverging circular beam, narrow emission spectrum with reduced temperature sensitivity, low-cost manufacturability, simpler coupling optics, and increased reliability, especially at high temperatures. They can emit very high power with very high power density as they can be conveniently configured into large two-dimensional arrays and modules of arrays. We report recent development on such high-power, high-efficiency 808nm VCSELs with industrial leading similar to 55% power conversion efficiency (PCE). Top emitting VCSELs were grown by MOCVD and processed into single devices and 2D arrays using selective wet oxidation process and substrate removal technique for efficient current confinement and heat removal. Peak PCE of 51% and peak power of 800W were achieved from 5x5mm array, corresponding to peak power density of similar to 4kW/cm(2). Pumped with new generation of 2.3kW VCSEL module, Q-switched laser pulse energy at 1064nm reached 46.9mJ, more than doubled from previously reported results.

A research has been carried out on the optimization of the shape of encapsulating cover to minimize optical losses in light-emitting modules fabricated with the “chip-on-board” (COB) technology. Optical properties of the components of a typical COB were taken into account including those of the substrate, light-emitting chips, encapsulating material and phosphor particles. Light losses were analyzed for various types of encapsulant surface structuring in an attempt to design an optical element with maximum light extraction efficiency. Calculations were complemented with experimental measurements. The results of the research showed that structuring the surface of the encapsulant can enhance light extraction by 10 to 15% for the material without phosphor particles and by 10 to 14% for the material with phosphor particles.

New types of phosphor (YAG:Ce 3+ : yttrium-aluminum garnet doped with Ce 3+ ions) containing glass-ceramics material was developed for light-emitting diodes (LEDs). The optical properties of the experimental samples were investigated and are reported on. Use of new phosphor material in white LEDs fabricated with the “chip-on-board” technology is demonstrated.

This article investigates the problem of light extraction from LED devices fabricated via chip-on-board technology and emitting in ultraviolet (UV) range (360-380 nm) of spectrum. The measurements of electrical and optical properties of devices with varying number and arrangement of semiconductor chips were conducted. Optimization modeling was performed with Zemax software. Modeling included the choice of substrate material, variation in the chip arrangement, and the change in the properties of the covering layer. All together, the accomplished study allowed us to elaborate the recommendations for improving the performance of UV LED devices. In particular, it was demonstrated that the optimization of chip arrangement on the substrate can provide 10 % increase in energy efficiency of LED modules.

Aims of this work were research of the material transfer properties influence on heat transfer and subsequent search of the heat dissipation optimization ways. Subject of the research was plastic heat sinks for retrofit LED lamps. To achieve this aims numerical simulations of free convection flow were performed which were coupled with simulation inside solid parts of the heat sink. In this study, parametrical researches took place. During this study, heat transport properties of the heat sink material were varied. Derived results allowed to make conclusion about optimal heat transport properties of the plastics which can be used in retrofit LED lamp production. In addition, some heat sink structure improvements were proposed.

This paper discusses the design optimization of LEDs fabricated using chip-on-board technology. Light losses are analyzed, and an attempt is made to create an optical element that maximizes the lightoutput efficiency from the chips. Experimental measurements of test samples are made, and optimization calculations are carried out using the ZEMAX software package. As a result of the studies, an optimized shape of the optical element is obtained that makes it possible to reduce the light losses in the device by 10% by comparison with the initial design. (C) 2014 Optical Society of America.

Aims of this work were research of the material transfer properties influence on heat transfer and subsequent search of the heat dissipation optimization ways. Subject of the research was plastic heat sinks for retrofit LED lamps. To achieve this aims numerical simulations of free convection flow were performed which were coupled with simulation inside solid parts of the heat sink. In this study, parametrical researches took place. During this study, heat transport properties of the heat sink material were varied. Derived results allowed to make conclusion about optimal heat transport properties of the plastics which can be used in retrofit LED lamp production. In addition, some heat sink structure improvements were proposed. Acknowledgement The authors thank the Ministry of Education and Science of the Russian Federation for support in carrying out the work (contract No 14.516.11.0085). References [1] F.E. Shubert, Light Emitting Diodes (Cambridge University Press, Cambridge, UK, 2006). [2] A. Lakshmanan, R. Satheesh Kumar, V. Sivakumar, M. T. Jose // Indian Journal of Pure & Applied Physics 49 (2011) 303. [3] L.G. Loitsanskiy, Mechanics of liquid and gas (Drofa, Moscow, 2003). [4] H.K. Versteeg, W. Malalasekera, An Introduction to Computational Fluid Dynamics (Pearson Education Limited, England, 2007). 182 И.Н. Ивукин, В.Е. Бугров, А.Р. Ковш, М.А. Одноблюдов, А.Г. Шалковский, А.Е. Романов

The effect of light scattering in phosphor-containing optical coatings on energy losses in chip-on-board LED devices is considered. The energy losses have been evaluated by numerical simulation with the refractive index of the coating material (n = 1.4–1.8) and the average radius of dispersed phosphor particles (R = 5–50 μm) being the variable parameters. It is established that the energy losses most significantly depend on the level of total internal reflection at the coating/air interface. In the LED device configuration studied, the optimum refractive index of the coating material is n = 1.4. It is also found that, in order to reduce the energy losses related to light scattering on phosphor particles, it is expedient to use phosphors with coarse particles (R = 50 μm).

We have considered energy efficiency of two red-blue LED-based lighting systems prospective for use in horticulture. The first one used LED chips emitting at 455, 660 and 730 nm, and the second one was based on blue 455 nm chips and a red phosphor with peak emission wavelength of 670 nm. The research has shown that at equal emission proportions at the specified peak wavelengths, the chip solution was 5 % more energy-efficient at phosphor concentration of 1 %, and 8 % more efficient at 10 % of phosphor.

The current state of the field of semiconductor lasers operating in the spectral range near 1.3 μm and with an active region represented by an array of self-organized quantum dots is reviewed. The threshold and temperature characteristics of such lasers are considered; the problems of overcoming the gain saturation and of an increase in both the differential efficiency and emitted power are discussed. Data on the response speed under conditions of direct modulation and on the characteristics of lasers operating with mode synchronization are generalized. Nonlinear gain saturation, the factor of spectral line broadening, and the formation of broad gain and lasing spectra are discussed.